The diet of an invasive nonnative predator, the feral ferret , and implications for the conservation of ground-nesting birds

Thomas W. Bodey (1, 2) , Stuart Bearhop (2) , Robbie A. Mcdonald (3)

1 QUB - Queen's University [Belfast]
2 Centre for Ecology and Conservation
3 Food and Environment Research Agency

Introduced carnivores have had a significant impact on the fauna of a number of countries, particularly on islands. In the British Isles, several offshore islands holding internationally important aggregations of seabirds and shorebirds support self-sustaining feral ferret populations, often as the top terrestrial predator. However, little is known about the interactions between ferrets and both native and nonnative prey in these locations. We examined the diet of feral ferrets on Rathlin Island, Northern Ireland. We determined the frequency of occurrence of prey items and constructed energetic models to determine their potential impact on both native and introduced prey. Rabbits occurred in 75% of scats, while birds, carrion, and brown rats were important secondary items. There was little difference between the diets of males and females. Estimates of the energy requirements of the population at current, and with hypothetically reduced, rabbit availability revealed the potential for carrion to maintain the ferret population over winter. Management options could thus focus on reducing anthropogenic food sources as an immediate way of mitigating the threat to ground-nesting birds, while other strategies, including eradication, are considered.

Mots clés: Hyperpredation; Invasive species; Island; Management; Mustelid

Thomas W. Bodey, Stuart Bearhop, Robbie A. Mcdonald. The diet of an invasive nonnative predator, the feral ferret , and implications for the conservation of ground-nesting birds. European Journal of Wildlife Research, 2010, 57 (1), pp.107-117. ⟨10.1007/s10344-010-0404-y⟩. ⟨hal-00599783⟩